1. Field of the Invention
This invention pertains generally to grain drills.
2. Description of the Prior Art
Unlike row type planters, such as used for corn that may require transverse furrow spacings of 10 inches, grain drills are designed to plant at furrow spacings of 10, 8, 7, and even 6 inches or less. Therefore, the relatively movable, individual grain drill planting apparatuses are located on the drill transverse to the direction of travel frequently at the noted smaller intervals. Further, they are often staggered longitudinally along the grain drill also in the noted 6 inches or less interval. Inasmuch as the seed for all of the apparatuses, and fertilizer where desired unlike other planters, are stored in a transversely extending hopper forward of the apparatuses with seed tubes, and sometimes fertilizer tubes, extending from the hopper to the disk openers for depositing into the furrow created, each apparatus may also have a further reduced transverse width. A part of the apparatus is the press wheel which is located in line and behind the disks to close the furrow, compact the soil, and gauge or control the depth of the disk furrow openers for desired seed depth placement.
Although individual depth control is desired for seeding in varying soil and moisture conditions, the convenient provision of this adjustment in the reduced spacings between furrows and the narrow size apparatuses creates a problem. Further, the adjustment should be accessible from the rear of the drill and rearward of the press wheels. Preferably, it should be able to be accomplished by one hand and provide predetermined positive increments over a considerable range and have indicia indicating each position so that all apparatuses can be set to this position if desired. Also once set, the adjustment should be maintained against the spring load exerted by the pressure rod on the structure supporting the disk openers which forces same into the soil against the restraint offered by the press wheel in this gauging function. To date, Applicant is unaware of a planting apparatus that achieves these objectives and that does so in a convenient and practical manner.